(CNN) -- Marin Cilic fired off 20 aces and hit 63 winners to knock Andy Roddick out of the quarterfinals of the Australian Open in a major upset in the season's first Grand Slam on Tuesday in Melbourne.

Cilic topped Roddick 7-6 (7-4), 6-3, 3-6, 2-6, 6-3.

The win by the No. 14 seed came after a nearly four-hour marathon match, including a 70-minute first set that ended with a tiebreak.

Roddick, whose fastest serve reached 220 kilometers/hour, nailed 15 aces and had 47 winners. But Cilic edged the American on winning percentage on first serve, 75 to 69.

Cilic also earlier took down U.S. Open champion Juan Martin Del Potro. Next up for the Croatian will be the winner of a match later Tuesday between Andy Murray and Rafael Nadal.